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Why does lithium fuse at lower temperatures than hydrogen?
This is a basic question, but it's been bugging me. In the Wikipedia article for lithium burning, it states that:
Stars, which by definition must achieve the high temperature (2.5 × 10^6 K) necessary for fusing hydrogen, rapidly deplete their…
Sir Cumference
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Can I leave a planet without achieving escape velocity?
I know that if you exceed orbital velocity, you will never fall-back to the planet. My question is not about orbits. It's about brute-force propulsion to achieve altitude. I'm using an intentionally slow velocity to help illustrate my point.…
user3384842
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Are Gamma Ray Bursts of galactic or extragalactic origin?
I read about the 1995 Lamb-Paczynski debate on whether GRBs are galactic or extragalactic in origin. With our current experimental evidence, have we found whether GRBs are galactic or extragalactic?
ROBOTPWNS
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Is it possible that Mercury was originally the moon of Venus after a giant impact?
Mercury looks like the Moon, and so it makes me think about a question: is it possible that Venus and Mercury were the a same planet originally, and a giant impact with that planet made it split into Mercury and Venus (like with the Moon and Earth)?
Gstestso
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Would Adaptive Optics be Useful in Radio Astronomy?
The question Why is this video showing radio waves transmitted from a radio telescope? and this answer to it got me thinking. If atmospheric seeing at visible wavelengths is the result of refractive index inhomogeneity, would it also be a similar…
uhoh
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Will gravitational waves too far away ever reach us?
Gravity is the curvature of spacetime, and its effects travel at lightspeed. However, space is expanding; eventually, light from distant galaxies will become more and more redshifted, and we will no longer be able to see them (source).
As such,…
Sir Cumference
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Why can we detect gravitational waves?
Now that LIGO has finally measured gravitational waves using a huge laser interferometer, to me, the question remains, why was it possible? As it is explained in many news articles, gravitational waves are similar to water waves or electromagnetic…
Keinstein
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Why does the planet Saturn have numerous (62) moons compared to the rest of the planets in the Solar System?
Saturn is a gas giant like Jupiter. It has everything from
tiny moonlets less than 1 kilometer across to the enormous Titan, which is larger than the planet Mercury. Saturn has 62 moons with confirmed orbits.
Wikipedia
Why does Saturn have more…
Dr.Ebe
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How does light affect the universe?
When light is emitted by for example a star, that star loses energy - which causes it to reduce its gravity. Then that energy begins a journey for potentially billions of years, until it reaches some other object.
When that light reaches a surface,…
frodeborli
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Are there ever any simultaneous transits of both Mercury and Venus as seen from the Earth?
Transits of Mercury happen fairly frequently due to its short period, but transits of Venus are less frequent. I've looked over the data available to me and found that there have been transits of both planets in the same calendar-year in 1631 (Nov…
Cyberherbalist
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On the cosmological principle
Just more of a conceptual question on the mutual inclusivity of the cosmological principle. That is to say, I was wondering if it were possible to have a Universe that were isotropic but NOT homogeneous OR a Universe that were homogeneous but NOT…
MichaelJRoberts
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How does a telescope measure parallax angle?
I know how stars' distances are measured by using parallax, but I want to know how the actual telescope measures the parallax angle. Any helpful links/ explanations are needed.
anna 1234
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Do asteroids have a gravitational field?
I know that asteroids are huge chunks of rock, orbiting a solar system. Do asteroids have a gravitational field and do they gravitationally attract each other to form planets?
Austin Phillips
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What is the composition of an asteroid in percentages?
I am developing a RPG game (or so I like to tell myself) within outer space. Within the game, players would be able to mine small asteroids and collect resources, in order to make money. I'm having some difficulty determining exactly how much of the…
Thomas Reinstate Monica Myron
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Is there an upper limit to the mass of terrestrial planets?
The exoplanet Kepler-10c has a mass between 15 and 19 times the mass of the Earth (making it comparable in mass to Neptune), and yet is thought to have a density of about 7g/cm3 and to be a terrestrial planet, with a substantial proportion of "hot…
James K
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